When Suki recalled her past to her friends she described her deep bond and friendship with her brother Shinji as well as his characteristics. She remembered how he never got in trouble, he never misbehaved. He was a kind-hearted person, did what their father asked of him and Shinji even got straight A's in school (Suki commenting this making him the whole package).
About five years before the events of the series, Shinji disappeared, and when Suki had came home, she found her parents visibly sad, her mothers face was just blank and all she could say was "it wasn't because he was bad". And her father said Shinji is okay "he's just not with us and we need to move ahead with our lives, one day you'll under stand". She believed he was dead although she has never aware of the actual circumstances.

When he arrives at Tower Prep, Shinji is seen speaking with Headmaster, saying "my father insists" (later learned to be up-grading Whisper 119). Suki upon seeing this retreats back to her friends, wondering if she really had seen her brother, but is questioned her friends that maybe she saw something else. The second time he is seen he is again speaking with headmaster though his time about his stay at Tower Prep, Headmaster offering a room to stay in. Headmaster is also heard saying "I want them as scared as I was when I first came to Tower Prep", hinting headmasters motive of using fear to control the students and Shinji laughing with him at his words.

When Suki is working in the observatory Shinji comes in behind her, spooking her. He seems very happy to see his sister again after all these years and promises they can be friends again like they were before after she graduates from Tower Prep. He claims to have also used the observatory in his day what for is unknown, hence his knowing its secret location. His mission at Tower Prep is later explained to be deactivating Whisper 119 and replacing her with Whisper 120. When Suki, Gabe, CJ and Ian try to go to the abandoned building and use their pirated signal, he appears and blocks their way, already knowing that they have something planned that doesn't follow "The Program". Suki asks Shinji to join them and escape, but his feeling of responsibly to his family is too strong. He takes out his PDA, notifying Whisper. Ian kicks him and their fight begins. He uses his double image ability to confuse Ian, but ultimately, the students escape from him as he calls for an alarm.

Shinji is called by Suki who is pretending to be his father. She tells him to come back home. Immediately after the call, Shinji calls the number back, asking if he should bring Suki home like they discussed. Suki answers no, saying that it was reconsidered. Shinji appears in Suki's room telling her that her father never asked him to bring her home and saying, "you've added deception to your skills of mimicry." He tells her that he is taking her home to father, and states that it wasn't because Tower Prep was bad for her, but that she was bad for Tower Prep. At the end of the episode, he has two men carry Suki out of a room saying, "We're going home to father." ("Snitch")

Shinji's ability is to create an illusionary duplicate of himself, which he can use to confuse an opponent in combat. It is unknown whether the duplicate is an actual optical image or some kind of hallucination that he can induce others to see.